View all sites I am part of

[agneum]

Is there a page from where you can see all the sharepoint sites you are part in? The front page only shows the pages you are follwing, which isn't very helpful.

Furthermore, when moving files between sites, you can't select a target destination site without you having "followed" it first. Is there anyone working to improve the aspects of UX/UI for Sharepoint, it's been like this for years.

[#2]

Hi,
No, there is not. You can see the site you have access to based on how frequently you work there in the SPO landing page and also in OneDrive for Business

[#3]

@agneum 
This is a generic problem. You can use search to provide you with that list. i.e. search for

(contentclass:"STS_Site") (contentclass:"STS_Web")

See https://sharepoint.stackexchange.com/questions/213926/contentclasssts-site-or-contentclasssts-web-is...
NB: search results are security trimmed so you will only see sites you have at least read access to.

There are 3rd party apps that use this approach to generate this list.
Paul | SLIM Applications

[#4]

@Paul_HK_de_Jong 

Sorry, I am a bit ocnfused. Where is this "search" located ?

[#5]

@agneum 
Assuming you are on SharePoint Online use the following search query

https://<tenant>.sharepoint.com/_layouts/15/search.aspx/siteall?q=(contentclass%3A%22STS_Site%22)%20...

The trimduplicates is necessary to get full list. This query will list all site collections and the subsites your account has access to because the search results are security trimmed.
It is a basic list.

If you need sorting (e.g. alphabetical), hierarchy (subsites shown below site collection) with  indentation for subsites, current titles, exclude certain sites, ... then you need to start coding or use 3rd party apps. For example, if you hover over a site it will show the link.

Paul